<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    *{
        margin: 0;
        padding: 0;
    }
    ul{position: relative;
        list-style: none;
        width: 400px;
        height: 400px;
        background: red;
        margin: 400px auto;
        animation: one 1s infinite;
    }
    li{position: absolute;
    top: 0;
    left: 200px;
        width: 100px;
        height: 200px;
        background: pink;
        border-radius: 0 200px 200px 0;
        transform-origin: bottom left;

    }
    li:nth-child(2){
        transform:rotate(90deg);
        background: yellow;
    }
    li:nth-child(3){
        transform:rotate(180deg);
        background: green;
    }li:nth-child(4){
        transform:rotate(270deg);
        background: gold;
    }
    @keyframes one{
        from{
            transform: rotate(0);
        }
        to{
            transform: rotate(360deg);
        }
    }
    </style>
<body>
    <ul>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </ul>
</body>
</html>